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Studies on the influence of thermal water from Western Romania upon Amphibians

Abstract:

Under conditions of high and constant temperatures of thermal waters, aquatic Amphibian species can not start hibernating, and therefore remain active in winter time. The influence of thermal water is especially noticeable upon the Marsh Frog Rana ridibunda, which is present in all studied thermal habitats, and to a lesser extent, upon the species ,Bombina bombina, which can be found in two habitats. The life cycle of Rana ridibunda populations inhabiting five thermal habitats from Western Romania is characterized by lack of hibernation, an early and extended period of reproduction, and an increased frequency of tadpole gigantism. In all of these studied sites the species is able to reproduce successfully. We found giant tadpoles in three of the thermal habitats investigated, but not in other nearby non-thermal sites in the region. Besides Rana ridibunda, during winter time we also found isolated individuals of more terrestrial species like Rana dalmatina, Triturus cristatus and Triturus vulgaris in thermal habitats. These are terrestrial species that hibernate at the level of substratum of aquatic habitats, which is impossible in thermal waters; thus, they remain active in the cold season.